This paper proposes a virtual prototyping system for digital fabrication of multimaterial prototypes. It consists mainly of a topological hierarchy-sorting algorithm for
processing slice contours, and a virtual simulation system for visualisation and optimisation
of multi-material layered manufacturing (MMLM) processes. The topological hierarchysorting algorithm processes the hierarchy relationship of complex slice contours. It builds a
parent-and-son list that defines the containment relationship of the slice contours, and
subsequently arranges the contours in an appropriate sequence which facilitates optimisation
of toolpath for MMLM by avoiding redundant movements. The virtual simulation system
simulates MMLM processes and provides vivid visualisation of the resulting multi-material
prototypes for quality analysis and optimisation of the processesThe authors would like to acknowledge the Research Grant Council of the Hong Kong SAR
Government and the CRCG of the University of Hong Kong for their financial support for
this project.Mechanical Engineerin
